Double-billet extrusion press



P. BILLEN ETAL 2,969,873 DOUBLE-BILLET EXTRUSION PRESS Jan. 31, 1961 2 Sheets-Sheet 1 Filed May 17, 1 95? Jan. 31, 1961 P. BlLLEN ET AL DOUBLE-BILLET EXTRUSION PRESS 2 Sheets-Sheet 2 Filed May 17, 1957 INVENTORJ J BL'ZZen Z(/.' L

ihhei' t ATTORNEW instance aluminium billets 3, are inserted.

United States Patent DOUBLE-BILLET EXTRUSION PRESS Peter Billen, Leverkusen-Kuppersteg, and Willi Linnerz, Dusseldorf-Eller, Germany, assignors to Schloemann Aktiengesellschaft, Dusseldorf, Germany Filed May 17, 1957, Ser. No. 659,982

Claims priority, application Germany May 19, 1956 3 Claims. (Cl. 207-4) In extruding with double-billet presses, particularly in the production of cable sheathings by means of such presses, there is a risk that owing to the working on the two sides not being quite uniform, or owing to the billets supplied on the two sides not being of the same size, in the course of a number of strokes of the press differences may occur in the container contents, since the extrusion ditierences in the successive working strokes are additive. Some possibility must therefore be provided for eliminating such differences, in order that the contents of the two containers of the double-billet press may always be as equal as possible in magnitude.

This invention relates toa method for equalizing unequal container contents of double-billet presses, particularly of double-billet cable-sheathing presses. The method according to the invention consists in the feature that during the compression of the fresh billet and the contact pressing of the contents of the container, and in fact until the normal extrusion speed is attained, equal forces are exerted upon the two press rams, and that the equalization of the contents is eifected only during the extrusion, after the attainment of about normal extrusion speeds of the two rams, by a slight variation of the extrusion speeds of the two rams. The exerting of equal forces upon the two rams may be elfected, for example, by a hydraulic connection between the two hydraulic pressure cylinders in which the press rams are slidably disposed. In the method of the invention it is therefore, amongst other things, important that the equalizing should not be eifected during the contact pressing, and that during extrusion it should only take place gradually; for the difference between the speeds of extrusion of the two rams must remain so small that no curving or other misshaping of the issuing cable sheath or extruded rod occurs.

By contact pressing is meant the pushing of the fresh billet against the extrusion residue, so that the residue and the fresh billet become welded together.

The invention also relates to a controlling device for carrying out the method in accordance with this invention. Fig. 1 is a diagrammatic view showing an extrusion press and control means therefor constructed in accordance with this invention; and,

Fig. 2 is a view similar to Fig. 1, and showing an accumulator and motor driven pumps for providing pressure fluid to the press.

In a press head 1 constituting a container there are two container bores 2, into which material for extrusion, for 4 and 4 denote two extrusion residues, unequal in size, from the last extrusion. The cable to be sheathed runs through the press head 1 in the direction of the bore 5 in a manner known in itself. The two billets 3 are pushed in by press rams 6, which are mounted on pistons 7, which are slidable in cylinders 3. For the introduction of the billets and for the compression and contact pressing of the same, liquid under pressure is admitted into cylinder spaces 8a. The two pressure spaces 8a are connected with one another by a pipe 9, in which there-is a shut-off control valve 10, which can be actuated by means of a solenoid 11. By way of the pipe 9, therefore, according to the position of the control valve 10, a connection between the two pressure spaces can be established or interrupted. For extruding the billets, liquid under a high pressure is forced into the pressure spaces So from pipes 12 and 12a. In the pipes 12 and 12a there are non-return valves 13, which permit pressure liquid from these pipes to enter the cylinders, but prevent any return of pressure liquid from the cylinders.

The pipe 12 is connected to a pump 54 and the pipe 12a is connected to a pump 53. Inlet pipes 56 and 57 from pumps 53 and 54 respectively communicate with a liquid reservoir 55 from which liquid is supplied to the pumps 53 and 54. A common motor 50 drives pump 53 through shaft 51 and also drives pump 54 through shaft 52. By reason of this arrangement, pumps 53 and 54 are driven at exactly the same speed and consequently deliver substantially the same quantity of pressure liquid per unit of time to the pipes 12a and 12 respectively and to the pressure spaces 8a in the cylinders 8.

In order to control the operation of the pistons 7 during an extruding operation there is provided a synchronizing valve 14 connected by a pipe 27a to the space 8a in one cylinder 8 and connected by a pipe 27b to the space 8a in the other cylinder 8. The valve 14 is provided with a slide 22 to which is fixed a rod 21. The rod 21 is connected by a pin and slot or equivalent connection to one end 23 of a pointer 24 which is pivotally mounted at 25. The free end of the pointer is disposed adjacent a scale 26 to provide an indication for a purpose to be presently described.

A rack 15 is fixed to one piston 7 and a second rack 15 is fixed to the other piston 7. The two racks 15 are disposed in spaced parallel relationship and meshing with the two racks 15 is a common pinion gear 16. Pinion gear 16 is rotatably mounted on a rod 17 which is pivotally connected at 18 to one end of a regulating lever 19 pivotally mounted at 20. The opposite end of the lever 19 is connected by a pin and slot or equivalent connection to the rod 21.

The synchronizing valve 14 is also connected to a discharge pipe 30 in which is connected a throttle valve 31. A discharge pipe 39 is connected to the throttle valve 31. Rotatably mounted in the throttle valve 31 is a plug having a slot 34 and the plug may be rotated by the lever 32 to vary the area of the slot 34 communicating with pipes 30 and 39. I

Interlocking control means between control valve 10 and throttle valve 31 is provided in the form of a switch 35 connected to the solenoid 11 and disposed in the path of movement of the lever 32. In the position shown, lever 32 closes the throttle valve 31 and also closes the switch 35 which energizes the solenoid 11 to maintain the control valve 10 open. When lever 32 is moved in the direction of the arrow 33, the throttle valve 31 is opened and the switch 35 is also opened to de-energize the solenoid 11 and close the control valve 10.

In order to operate the pistons 7 for introducing billets 3 into the container bores 2 and for compressing such billets 3 to weld the same to the extrusion surpluses 4 and 4' and also to return the pistons 7 after completion of an extruding operation there is provided a source of pressure liquid in the form of an accumulator 60 which is supplied with pressure liquid through a pipe 65 from a pump 62 driven by a motor 61 there being an inlet pipe 64 connected to the pump 62 and to a liquid reservoir 63. The accumulator 60 is connected through a pipe 36 to a three-way main control valve 37 which is connected through pipes 42 to spaces 8b in the cylinders 8. The main control valve 37 is also connected through a pipe 40a and a reducing valve 41 with the space 8a in one In describing the operation of the apparatus of this. invention it is assumed that, an extrusion operation has been completed leaving extrusion residues or stumps 4 and 4 in the container bores 2 of the press head 1, that the rams 6 have been retracted and that new billets 3 have been placed in position for insertion into the container bores 2. At this time, the three-way valve 37 is operated to introduce fluid pressure from the accumulator 60 through the pipes 40a and 40b and the reducing valves 41 into the spaces 8a of the cylinders 8. This will cause movement of the pistons 7 and rams 6 to force the billets 3 into the container bores 2 and to compress such billets and weld the same to the extrusion residues or stumps 4 and 4'. During this portion'of the operation, the control valve 10 in the pipe 9 is open thereby maintaining equal pressure in the spaces 8a of the cylinders 8 and at the same time, the three-way valve 37 permits exhaust of fluid from the spaces 8b in the cylinders '8 through the pipes 42 to the three-way valve 37 and through the discharge pipe 38 connected thereto. This operation, however, will not result in extrusion of the stumps 4 and 4' and the billets 3 since the pressure reducing valves 41 are adjusted in such a manner that the pressure introduced into the spaces 8a of the cylinders 8 from the accumulator 6th is insuflicient to result in an extrusion operation. Extruding of the metal is to be accomplished in a manner to be presently described.

One of the billets 3 may be of greater length than the other billet or the extrusion residues or stumps 4 and 4' may be of different lengths and for these reasons or for possibly some other reason, one of the rams 6 may lead the other ram 6 during introduction of the billets 3 into into the container bores 2 and contact pressing of the same with the stumps 4 and 4' to cause welding between the stumps and the billets and in the event this occurs and one ram 6 leads the other ram 6, this fact will be indicated by the pointer 24 on the scale 26 in that, the pinion gear 16 and the rod 17 connected thereto will be displaced by the action of the racks connected to the piston 7 and such displacement of the rod 17 will result in pivotally moving the lever 19 which in turn will move the rod 21 and slide 22 of the synchronizing valve 14 to the right or to the left depending upon which piston 6 is leading the other. If the slide 22 of the synchronizing valve 14 is moved toward the left, as viewed in Fig. 2,-- this' would permit exhaust of fluid from the space 8a of the lefthand cylinder 8 through the pipe 27b, the port 28b in the synchronizing valve 14 and a recess 29b to the discharge pipe 30'. Similarly if the slide 22in the synchronizing valve 14 were displaced toward the right as viewed in Fig. 2, pressure fluid would exhaust from the space 8a of the righthand cylinder 8 through the pipe 27a, the port 28aand a recess 29a in the synchronizing valve 14 to the discharge pipe 30. However, at this time,

the throttle valve 31 is closed and therefore, pressure fluid cannot pass from the discharge pipe 30 to the discharge pipe 39 leading from the throttle valve 31.

prevented by the setting of the three-way valve 37, but at the same time, such valve permits escape of fluid from the spaces 8b of the cylinder 8 through the pipes 42 and the three-way valve 37 to the discharge pipe 38 connected thereto.

At thestart of the extrusion operation by pressure fluid delivered from the pumps 53 and 54, the operator ascertains trom an inspection of the pointer 24 with relation to the scale 26 as to whether or not one ram 6 is leading the other or as to whether such rams are in corresponding position. in the event pointer 24 points to zero on the scale26, this indicates that the rams 6 are incorresponding positions and that the same should be permitted to move forward during the extrusion operation at the same speed. Consequently, the operator will at this time move the handle 32 on the throttle valve 31 in the direction of the arrow 33 to open such throttle valve and this operation will, at the same time, open the switch 35 to deenergize the solenoid 11 and close the control valve 10. Since operation of the throttle valve 31 to open the same will result in establishing corrmqunication between discharge pipe 30 and the discharge pipe 39, thereafter dur- Upon completion of the charging operation during I which the billets 3 are introduced into the container bores 2 and welded to the extrusion residues or stumps 4 and 4',

the three-way valve 37 is'operated to prevent flow of 1 the spaces 8:: of the cylinders 8 and the pressure provided by pumps 53 and 54 is suflicient to'cause extrusion metal from the containers 2 of the press head 1. Flow of fluid from the pipes 58 and 59 to the accumulator 60 will be ing the extrusion operation, the control of the relative positions of rams 6 will be entirely automatic by reason of the fact that any variation in the relative positions of rams '6 will cause movement of the slide 22 in the synchronizin'g valve 14 either to the right or to the left and in the event of such movement, pressure fluid will be exhausted from the space 8a of the cylinder 8 of the piston 7 which is leading the other pistons thereby result in slowing down the movement of such piston until the same occupies a position corresponding to the other piston 7. i

In the event, however, that upon starting the extrusion operation the pointer 24 indicates that one of the rams 6 is leading the other ram 6, the operator may very slowly move the lever 32 to open the throttle valve 31 thereby establishing a restricted communication between the discharge pipe 30 and the discharge pipe 39 and, of course, at the same time, this movement of the lever 32 will result in opening the switch 35 which will serve to de-energize the solenoid 11 and close the control valve 10. By this operation, pressure fluid is permitted to exhaust very slowly from the space 8a of the cylinder 8 in which the piston 7 is leading the other piston to slow down the leading piston until both pistons occupy corresponding positions as indicated by the pointer 24 pointing to zero on the scale 26 and when this condition has been reached, the throttle valve 31 may be fully opened to thereafter allow complete automatic control of the relative positions of the rams 6. The throttle valve 31 is only opened a small amount during balancing of the positions of rams 6, since a rapid change in the relative positions of the rams 6 might result inan inferior extruded product and therefore, this change in relative position of the rams 6 is accomplished at a relatively slow rate in order to main tain the quality of the extruded product.

Upon completion of the extrusion operation the threeway 'valveis moved to a position to admit pressure fluid fromthe accumulator 60 through the pipes 42, the spaces 8b of the cylinders 8 which will result in retracting the piston 7 and rams 6 carried thereby and, of course, in order to permit this operation, delivery of pressure fluid from the pumps 53 and 54 has been stopped and the fluid'in the spaces 8a of the cylinders 8 will be exhausted through the pipes 27a and 27b, the synchronizing valve 14 and-the discharge pipe 30 to the discharge pipe 39. Upon completion of retraction of the pistons 7 the throttle valve 31 will be closed by the operator, which operation will also close the switch 35 thereby energizing the solenoid 11 and opening the control valve 10 to reestablish communication between the spaces 8a of the cylinders 8 through the pipe 9.

It will be seen that by the above described invention there has been provided an apparatus in which billets may be introduced into the container bores of a press head by the application of equal pressure thereto which will result in compressing the billets and welding the same to the extrusion residues or stumps remaining in the container bores from a preceding extrusion operation and that thereafter the extruding operation may be accomplished by the pressure fluid supplied from two separate pumps operated in synchronism to deliver equal quantities of fluid per unit of time and in the event one of the press rams leads the other mechanism is provided to slow down the leading ram until such rams occupy, corresponding positions after which operation of the apparatus during extrusion is entirely automatic and will maintain the rams in corresponding position.

It will be abvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification, but only as indicated in the appended claims.

We claim:

1. A double billet extrusion press comprising a press head, opposed billet containers in said head, two opposed cylinders, two rams for engaging and pressing billets one in each container, two pistons connected one to each ram and slidably mounted in said cylinders, means for feeding pressure fluid to each cylinder, a pipe connecting said cylinders for maintaining equal pressure therein, a control valve in said pipe, a synchronizing valve having pressure fluid inlets connected to each cylinder, a pressure fluid outlet on said synchronizing valve, a throttle valve in said fluid outlet, actuating means for said synchronizing valve comprising toothed racks fixed one to each piston and movable therewith and a pinion gear meshing with said racks and having an axle, said axle being connected to said synchronizing valve, whereby upon movement of said pistons at the same speed said axle will remain stationary and said synchronizing valve will be inoperative, but upon movement of one piston at a greater speed than the other piston, said axle will move to actuate said synchronizing valve to release pressure fluid from the cylinder of said one piston through said throttle valve to reduce the speed of said one ,piston thereby synchronizing the movement of said pistons.

2. A double billet extrusion press as defined in claim 1, in which a solenoid-activated shut-off valve is connected between the spaces in the closed ends of said cylinders, and in which an interlocking control means is provided between said control valve and said throttle valve to by-pass said control valve through said shut-off valve when said throttle valve is closed and to close said shut-off valve upon opening said throttle valve.

3. A double billet extrusion press as defined in claim 1 wherein said means for feeding pressure fluid to each cylinder comprises a low pressure system for feeding pressure fluid to said cylinders to position said rams and a high extrusion pressure system including a pair of pumps and a common motor for driving said pumps to deliver substantially equal quantities of pressure fluid per unit of time to said cylinders respectively.

German application Sch 14,600 Ib/7b, printed March 1, 19 56,. 

